Here's a topic guaranteed to start controversy. Which Linux distribution is best? It all depends on your criteria for judging. Even then the topic is highly subjective. Here are a few nominees for "best distro" in specific categories.

CentOS is great. Arch is great. But I mainly use Debian. Nothing against CentOS or Arch and they all meet my needs. But I am used to Debian. I started with Debian and I simply have no reason to switch over for good.